I have an old install of Backtrack 5 amd64 and yesterday i tried to upgrade it.
For some reason that upgrade failed and i cannot manage to get it working.
So I now want to copy my data from some file locations to an external hard disk in order to perform afterwards a clean install with ubuntu.
I booted a live usb with ubuntu and i am able to see the files within the file explorer. However some of the i cannot copy i.e. do not have sufficient permissions.

Provided I know the root password of my original backtrack installation
How can i mount it using this password from the ubuntu live cd so that i can do any file operations with granted permisions???

if you copied the files to an ext filesystem, the files' access rights and ownership will be changed to root.. so you might have to change to your normal user.. you could do it using commands in terminal or open nautilus with root rights, right-click files to change the files and from the menu choose Properties -> Permissions to change them graphically...
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preciseJan 27 '14 at 13:22